Unloader for pump drives



' Dec. 3, 1929.

H. E. BUCKLEN ET AL UNLOADER FOR PUMP DRIVES Filed Sept. 10, 1926 3 Sheets-Sheet l Dec. 3, 1929. H. E. BUCKLEN ET AL UNLOADER FOR PUMP DRIVES Filed Sept. 10. 1926 3 Sheets-Sheet 2 Dec. 3, 1929. H. E. BUCKLEN ET AL UNLOADER FOR PUMP DRIVES Filed'Sept. 10. 1926 3 Sheets-Sheet 5 Patented Dec. 3, 1929 UNITED STATES tries HERBERT E. BUCKLEN AND HARLIE 0. PUTT, OF ELKHART, INDIANA, ASSIGNORS TO SAID HERBERT E. BUCKLEN, OF ELKHAR'I, INDIANA UNLOADER FOR PUMP DRIVES Application filed September 10, 1926. Serial No. 134,684.

as that commonly employed to connect a windmill to a water pump. While the unloader is shown as between a wind driven impeller and a water pump it is not to be limited to this use.

It is well known that the wind velocity re quired to start a wind driven impeller from rest is much greater than the velocity required to keep it turning after once the impeller is in motion due to the fact that the area of the impellers surface is comparatively small and the resultant torque practically nil at zero impeller speed. However, if the propeller is free to start to turn even at a relatively low wind velocity, the torque rapidly increases generally as an exponential function of the R. P. M. That is to say, the impeller of a windmill for driving a pump or the like, has a shunt motor characteristic.

Now, since there is relatively little energy I in.low wind it becomes important to have an impeller the inertia of which may be quickly and easily overcome so that full advantage may be taken of any puffs of wind. It was found that for a given diameter and pitch that a lighter impeller will respond to the winds of low velocity and accellerate faster than a relatively heavy impeller. Therefore, it is highly desirable that the weight be kept at a minimum consistent with strength.

Also, we find that even though the windmill impeller is made as light as practical, still it will not start readily underload. This is especially true when there are only low winds. Furthermore, when the impeller is used to operate a pump, especially those of the deep Well type, the resultant load is so great as to prevent the impeller from starting except at relatively high wind velocity.

The principal object of this invention is to provide mechanism for automatically d1sconnecting the impeller from the load or pump until the impeller is turning at a predetermined speed. Obviously, such a disconnecting feature will enable the impeller to start readily even at a very low wind value and to thus enable the operation of the pump down to the last vestige of the wind energy.

e are aware that it is common practice to provide automatic unloaders for engines and machines having the so-called shunt motor characteristics. For example, in the case of motor driven compressor units, automatic means is provided for disconnecting the motor from the unit until the motor attains the given speed so as to enable it to start freely. These devices, however, are not suitable for our requirements and we, therefore, propose to provide a novel unloader, particularly adapted for use in connection with well pumps.

The device of our invention connects the impeller to the load only when the impeller is revolving at a given R. P. M. Also, if after the connection has been made the wind suddenly drops to a low value, our unloader will respond thereto by decreasing the effective stroke of the plunger rod thus preventing overloading of the impeller during low winds. This arrangement enables the impeller to be responsive to any slight increase in wind value and prevent its complete stopping as long as there is a wind of above approximately twomiles per hour.

Other objects and advantages of our invention will more fully appear from the following detailed description taken in connection with the accompanying drawings which illustrate several embodiments thereof and in which Fig. 1 is a vertical sectional view partly in elevation of an unloader built in accordance with the features of our invention;

Fig. 2 is an elevation of the unloader shown in Fig. 1 with the exception that a different form of dust shield is employed to cover the moving mechanism;

Fig. 3 is an end view taken on substantially the line 33 of Fig. 1 looking downwardly;

Fig; 4 is an end view taken from the bottom of the construction shown in Fig. '1 looking upwardly; n

e- 5 esteeml e taken on the line i so is rocked. The shaft 22 extends to theo'ut- 5 of Fig. 1 looking in the direction indicated by the arrows;

Fig. 6 is a fragmentary view partly diagrammatic and partly sectional illustrating our u-nloader as applied to a wind driven P p;

Fig. 7 is a fragmentary view, in

ecti n. awn .tee e rgeis le. the jack or gear. mechanism I for reciprocating the pump plunger rod; and

Fig. 8 is a diagrammatic View of a modification of our invention.

Referring now to the; drawingsin detail in whichlike reference numerals designate similar parts throughout the several ivieiws, 10' denotes generally an unloaden. embodying the features of our invention, 6) This devicegisga'dapted' to be positioned between a I windmill construction such as that :disclosed' cured to horizontal' driving shaft 14 which. extends; into a gear casing-15 and is suitably journal'ed' therein. Th'e shaft 14' carries hetwe'n' its ends; a' worni16 which meshes with a wormwheel 17 secured to a shaft 1 8. The shaft 18 disposed atright angles'to the shaft 14 and-its suitably journ'aled within the casing 15 Fja'st'ene d to the shaft 18 asv disclosed in the c'o aen'ding' patent application previously mentioned, is a circular disc or crank member19 which has fastened theret e aneccentric pin 20. lVe preferably employ a gear reductionof tol as far as the worm l6 and the wormwheel17 areconcerned, scum the V plunger make s approiiilnatelytwo strokes to 7 ere-'rvtw'enty-four revolutions of the wind 1. wheel or impeller 13.

T he casing 15 isprovided with a lateral extension 21 in which is ournaledza pin'22 carryin ia ro cking" arm or'lever 23. The. shaft 22 an iarm 23" Skeydd thereto withirilhe .Hcas'i'ng; Thisgarm is slotted at 24 mare.

ceivesthe crank pin 20,".b'y which the shaft22 side hf-the'casihg extension 21. and on said outside end thearni 2?; iskeyed'. The'outei' Jend ofthe arih23 provided with n pin connectionto-the-plunger ro'dn25 of the p-um {rue gear casing =1.5 isxfasteneel to. a suppbrt member-26 :rotatably'moil-nted oniftop of a tower 27' (Fig. 6). YVe preferahlyprovide an anti-'frietidnalr support for .theanemher .26' by disposing a plural itv of anti-frictional b'alls 28 l5etweei1 the inembe'r 26 andthe top of. the

; towerv 27; Thesupport member 26 is .pre.

vided with a bore 29 through which 'the rodv 25..xtends- Disposed concentric .with this bore and secured to the support member 26 is a tube 30 which extends downwardly around the rod 25.

As best shown in Fig. 6 the support member 26 has fastened thereto a pivotable tail vane 81 which does not per se constitute a part of the present invention. The mounting for thetailvane 31 is fully described in the aforesaid copending patent application. Now, the wormwheeL'liis adapted to rotate in the direction indicated by the arrow in Fig. 7 and is at all times inmesh with the worm 16. The crankl roizites'with the worm wheel 17 and impartsa reciprocatory motion to the rod 25 through the lever 23. Due to the eccentric pint'and theslotted leg of the lever 23. a fast down and a slow up movement is imparted to the rod 25. This meansthat the rod. will be moved faster during the idling strokethan during the workin st-roke. Obviously,. this arrangement will result in a much more efficientpumpaction. a

. The lower end of the rod 25 is fastened to a yoke or cross liead member 32 of thc u'nloaderlO. The unloader 10 constitutes a slip connection between the reciprocatory rod 25 and a. pump plunger rod 34. The u ppcr end of the plunger rod 34.- is secured toa yoke or crosshead member 83 of the unloader 10 by The plunger rod 3-1 meansof a set screw 35. extends down through a conventional pump housing 36 having a discharge faucet 37 formed integral therewith. The upper end of the housing has threaded therein a packing gland 38 including a. packing'nut 89. T he housing 36 includes an extension 40 which projects down into the well and connects with a cylinder 41. The lowermost end of the plunger rod is secured to a piston 4.2 adaptedto reciprocatewithin the cylinder 41 which communicates through an orifice 13 with the water to be pumped. The piston 12 ma be of any conventional construction and may include any suitable valve mechanism. The

. plunger construct-ion shown does not constitute per se a part of our present invention but isillustrated to showthe relation between it andour novel nnloader. The invention is not limitedto the form of. pump shown. Any suitable pump may be employed. We shall nowproceed to describe in detail the unloaclcr 10. J s

I The yoke or cross head member 32 is con nected by a pair of cross rods 45 to a circular flange .46 I The upper ends of the truss rods ln are threaded and are secured tot-he yoke-member 32by means of nuts 47. Similarly the lower ends of the. truss rods 4: are fastened to the circular flalngre 46 by means of nuts 48 threadedthereon. It should be noted that the two truss rods 45 extend through.,. apertures 19 in, a circular flange 50 spaced from the flange 46.

The yoke member 33 secured thereto a izo pair of paralleltruss rods 51 which are fastened at their upper ends to the circular flange 50 by means of nuts 52. The lower ends of the rods 51 are secured to the yoke member 33 by means of nuts 53. The truss rods 51 extend through apertures 54 in the circular flange 46. i

The rods and 51 alternate in a circular path about the axis of the two flanges 46 and 50. These truss rods are preferably spaced 90 degrees apart. Of course, we desire it understood that although we have only illustrated four of these rods, the invention is not to be limited by this disclosure for any number of them could be employed without deviating from the features of our invention. The flange 46 is formed integral with a circular cylinder 55 which is disposed parallel to the truss rods. This cylinder 55 has a cylinder bore 56 in which a piston 57 is adapted to move. The piston 57 is formed integral with the circular fiange and has a circular bore 58. The lowermost part of the bore 56 of the cylinder has a circular shoulder 59 upon which is disposed an annular ring-like washer preferably made of cork. This ring of cork 60 constitutes a cushion or a seat for the lower end of the piston.

The circular f anges 46 and 50 on the cylinder and piston respectively. afford anchorage for the associated truss rods 45 and 51 and also act as guides or supports through which the free rods pass. That is to say, the rods 45 which are secured to the cylinder flange 46 are guided by the piston flange 50 and the rods 51 which are secured to the piston flange 50 are guided by the cylinder flange 46.

The rods 45 and 51 are made of such a length that when the assembly is completed the circular boss or extension 61 of the cylinder flange 46 will normally rest on top of the yoke or cross head 32 as is best shown in Fig. 1. Also, it should be noted that the piston flange 50 is provided with a circular boss or extension 62 which is normally spaced from the yoke 32 as indicated at 63 in Fig. 2.

As best shown in Fig. 1 it will be observed that the piston 57 fits relatively tight in the bore 56 of the cylinder 55. The hollow piston 57 is provided with a groove 64 preferably annular in shape and located a suitable distance from the extremelower end of the piston. The location of this groove depends on the length of the cylinder and this factor is to be determined by the maximum stroke re I quired as will become more obvious from the description which l'iereinafter follows.

The groove 64 communicates with the bore of the piston 57 by means of a plurality of holes 65 drilled on a downward slant, the purpose of which will also be explained later.

The cylinder 55 is provided with an annular groove 66 near its upper end and in its interior wall. This groove 66 is adapted to align with the groove 64 in piston-57 when said piston has entered the cylinder a given distance shown in Fig. 1.

The lower and open end of the hollow piston 57 is threaded internally to receive a valve cage 76 which is threaded externally to fit in the threaded end of the piston as indicated at 71. This cage is provided. with a tapered valve seat 7 2 adapted to have seated thereon a valve 78. Formed integral with the valve 7 3 is a valve stem 74 which extends through a valve guide 7 5 formed integral with a bracket 76 (Figs. 1 and 5). The bracket '76 preferably is formed integral with the circular part of the cage threaded into the piston. The guide 7 5 serves as a bearing for the valve stem 74 threaded its free end to receive an adjusting nut- 77 disposed on top of the bracket 76. The adjusting nut 77 is locked in position on the threaded end of the valve stem 74 by means of a set screw 7 8 threaded therein. A suitable spring 80 of the compression type positioned between the valve 7 3 and the bracket 76 and normally holds valve 7 3 open a definite degree determined by the adjusting nut 77. That is to say, this spring 80 serves to normally hold the valve 73 of. its seat 72. This spring 80 is preferably given just enough tension to insure the opening of the valve at a predetermined low reciprocal movement of the cylinder 55 as w ll be hereinafter explained. The head of the valve 73 is provided with a small drill hole 79. Instead of a drill hole in the valve head we may use a small slot filed in the valve seat.

Also it should be noted that we have provided the fiange 50 of the piston 57 with a small hole 82 having a plug 83 threaded therein through the boss 62. This plug serves to normally close the hole 82 but may be removed to facilitate the loading of the cylinder 55 with oil or for the purpose of replacing oil in the cylinder.

It should be noted that we have positioned between the packing nut 39 and the boss 84 of the cylinder flange 46 a spring 85 preferably of the compression type. This spring surrounds the rec. 34 and adapted to support the weight of the pump rod and piston and hold it in position and at the same tnne tends to cushion the circular flange 46 on the downward stroke. r. lso this spring serves to retard excessive downward movement. Figs. 1 and 2 illustrate the full downward position of the rod.

As previously mentioned, we have illustrated in Figs. 1 and 2 two different forms of dust covers for the piston and cylinder. With the exception of the cover, however, both of these views'illustrate identically the same de vice. Fig. 2 is a view showing the unloader of our invention turned degrees with re spect to the position of the device as shown in Fig. 1. In Fig. 1 the dust cover or shield 90 comprises a cylinder of flexible material such as cl th, canvas or leather, fastened at its endsto the flanges 50 and 46 of the piston 40 I slowly-causing the worm 16 and the worm wire and cylinder respectively. This cover isffastened at each end to the associated flange by meansof a wire twisted upon the fabric binding the same into a suitable groove provided in-the associatedmember. The flange -.has an annular groove 91 for receiving the 92 and the flange .46 has an annular groove-93 for receiving'the wire 94. (Fig.' 1). In Fig.2 we have illustrated a dust cover comprising a pair of telescoping cylinders '95 and--96. These sleeves or cylinders may me made of any suitable-metallic material. A smaller sleeve 95 is secured to the flange 46by means of screws 97 and the larger sleeve 96 is fastened to the flange 50 by means of screws .98. Either of these two types of duSt:Sl1l8lClS.ma' be employed for covering our .novel slip mechanism. It will thus be seen athatwe have-provided a dirt, dust and waterproof housing for both the piston and theicylinder.

The :operation of our device is briefly-as follows: The unloader isfirst properly connected to the rod 25 and the plunger rod 34: with-the @piston and cylinder in telescoping relation. "The spring '80 should be properly adjusted by means of the adjusting nut '77 prior :to the assembly of the device. Subsequent to the installation of the device in the pumping system, a suitable oil is placed in the eylinderthrough the filler hole 82 and the cylinder is preferably filled up to thevlevel of the valve bracket 76. lVe have designated the oil in Fig. 1' by'the reference character 100. "Of course, we desire it understood that any .other suitable imcompressible fluid may be used-in place of the oil.

-N ow as soon lightwindbegins to blow having a veloci-ty'of about three miles per hour, the impeller starts to turn over very whcel"17:-toturn. As previously pointed out, the worm '16 is adapted to t'urn'twelve times as fast asthe worm wheel 17. This rotary motion ischanged into reciprocatory motion means of the crank 19and the lever 23 and is transmitted to the rod 25. The rod 25 causes-theyoke or crosshead 32 to lift the cylfinder '55 :throughthe means of the truss rods 45. This movement causes the oil in the lower cndlof the cylinder to flow past the normally opened valve 73 into the hollow piston 57 expelling the air in the piston through thebre-ather hole 81. This upward movement of the cylinder continues slowly until the lower end of the piston has reached the lower endv of the cylinder and touches the leather upward movement and will lie against the truss rod. On ,the other hand, iftelescoping sleeves are employed asadnst shield, the lower sleeve xwlli merely be inserted farther into The oil in the piston is displaced by the air entering the piston bore 58 through the breather hole 81. This downward movement is accomplished at twice the speed of the upward movement due to the eccentric crank pin 20 and the slotted arm 24 of the lever 23. In other words, the rod 25 moves downwardly about twice as fast as it does upwardly. Despite the ditl'erentialstroke factor of the pump 'ack or lever 23. the valve 0 aenin is am )le to take care of the oil displacement in this stroke without retardation since its size is calculated with this feature in mind.

Upon the conclusion of the downward stroke, the parts will again be in the position shown in Fig. 1. Then too, due to the fact that the impeller is free to start unloaded, its speed has, during this stroke, slightly increased, so that upon the next upward movement of the cylinder the oil is displaced somewhat faster than on the previous movement. This results in an increased rush ofoil from the cylinder past the valve in the piston. The return stroke is accomplished in the same manner as previously described. Now when this oil pressure against the valve on the upward stroke is great enough to overcome the tension of the spring 80 and the weight of the valve, it quickly closes, trapping the remaining oil in the cylinder and owing to the incompressibility of the fluid, the rod 25 is enabled to lift the plunger rod to a distance equal to the balance of the upward stroke. That is to say, the trapped oil forms a. positive connection between the piston and the cylinder and causes them to move as a unit. Obviously, since the crosshead or yoke 33 is rigidly fastened to the rod 34, the rod 34 must of necessity move with the upwardly moving piston 57.

Moreover, if the space separating the boss 61 of the circular flange 46 and the crosshead or yoke 33 amounts to say two inches at the instant the valve is closed and the total maximum stroke is equivalent to five inches, then the pump rod 34 would be lifted a distance of three inches. On the return stroke of the rod 34 the two inch separation of the parts would be eliminated by the boss 61 again contacting with the yoke 33, and during the remainder of the downward stroke the pump rod and iston would be forced downwardly three inc es. As soon as the rod 25 is ready to make its next upward stroke, it will be found that the impeller is rotating at a still i faster speed. This will result in the next upward stroke occuring at a still faster rate causing the valve to close sooner than on the previous stroke and resulting in a less space separating the boss 61 from the yoke 38. This action will continue until the reciprocal speed of the plunger rod is such as to close the valve at practically the very beginning of the stroke, thus resulting in the maximum stroke being applied to the pump rod 34.

We preferably adjust the valve 73 to look at an impeller speed of approximately twentyfour R. P. M. It is evident that since the worm 16 turns twelve times as fast as the worm wheel 17, the rod 25 will make two strokes per minute. Viefind that this adjustment will permit actual pumping down to below a three mile per hour wind.

.Quite frequently it will be found that the propeller will start up quickly due to a sud den gust of wind and the valve will be closed.

A stroke or two will be made and then the wind will die down suddenly leaving the mechanism in the upward position. The

. spring in the pump rod or the vacuum effect in the pump barrel 41 draws the piston down rapidly enough to hold the valve 7 3 closed. Theweight of the pump rod acting against the worm on the propeller shaft will tend thereby to keep the valve closed so that theunloader does not automatically release. That is to say, themechanism will be locked on the upward stroke. It will be apparent that the drag or weight of the pump piston and the column of water above it, would pull downwardly on thepiston 57 through the rod 34 causing the valve to stay closed thus preventing the impeller from starting from this position in low winds, of say, three or four miles per hour.

lVe meet this condition by providing the small hole 79 in the valve head 73. The release may be provided by cutting a score or groove in the valve seat or the valve face to leakageiof oil past the closed valve. I the oil pressure falls below the valve tension form the bypass port, This hole afiords a slow release of the oil in the piston bore and hence if the aforementioned condition should occur, the load is gradually released by the When the valve opens thus releasing the load. This will permit pump piston 12 to fully resume its normal downward position until it is supported by spring 85. The main advantageof this construction is that it will permit the propeller to again start up without any load being imposed thereon. The size of the by-pass opening 7 9 in the valve head 7 3 is holes 65 as wellas with the groove 66 in the cylinder to collect and salvage any oil leaking past the piston from the lower end of the cylinder when the valve is locked and the oil is under compression. The seepage oil collected by the groove 66 is adapted to flow downwardly through the inclined holes into the bore 58 of the piston 57 on each working stroke. This arrangement prevents loss of oil which would be otherwise forced between the cylinder wall and the piston and out of the top of the cylinder due to the great pressure developed when the device is under load on the working stroke.

Obviously, when the reciprocal speed is low enough to permit the cylinder to be completely telescoped by the piston 57, a film of oil will be forced between the wall of the cylinder and the wall of the piston due to the high pressure created in the cylinder. This film of oil will be scraped off of the piston wall by the groove 66 formed in the internal wall of the cylinder 55. This groove 66 will collect the oil when the cylinder is moving downwardly and will discharge the same into the piston through the groove 6% and the drain holes 65, illustrated in Fig. 1. It should also be noted that the piston is provided at its lower end with a series of annular oil grooves 101, preferably three in number, which affords ample lubrication as far as the moving parts are concerned.

The previously described combination of grooves and oil holes prevents any loss of oil and at the same time permits ample lubrication of the piston and cylinder walls. The open end of the cylinder 55 is preferably beveled at 102 as shown in Fig. 1 in order to enable it to shed any moisture which mightcollect on the upper end of the piston 57.

Now we desire it understood that while this device, namely, the unloader 10, is primarily intended for use in connection with an impeller driven pump, that it is equally well applicable to any reciprocal. device where the release of the load is desired at some relatively low reciprocal speed and where the clutch action must be practically positive or nonslipping.

When operating a pumper, especially a pump of the deep well type, the resultant load is so great as to prevent the impeller from starting except at relatively high wind ve locity, but by employing an unloader such as that disclosed and described above, this load can automatically be eliminated temporarily so as to permit the impeller to start readily and easily even though it is subject to a rela- 'najted permitting the impeller to turn slowly a thus be responsive to any slight increase in wind value andpreventing its complete Stepp lFrom experimentation we found that by usmg our unloader the'impeller started from rest 1n a "four 'to' a five mile wind. and began pumping at the second or third stroke, or in "other Words,ithe impeller made twenty-four proximatelythree miles per hour.

' tothirty-six revolution sbefore the pump was connected'thereto by'our device. The pump continues to pumpwater with slightly-diminishing strokes down to a wind value of ap- Below this Wind value we found that our device functioned to disconnect the impeller from the load or the pump and thus permittedthe impeller torotate idly veryslow-ly 'until the wind droppedto below two miles perhour'at 'whic'hvaluethe impeller Will gradually-come toa' stop. I

We'alsoihave found thatwith awind having an average velocity value of approximately three miles per hour We can, by employing the construction disclosed in our "present application, pump approximately 67 gallons per hour. \Vith a Wind-velocity v'alue'of 16 miles per hour, we found that We could pump with our device 825 gallons per hour; the average stroke being 27 per minute and the average impeller speed being 330 revolutions'per minuteJ Also we'prefer- "ably'set the windmill 'to turn the propeller out offthe windwhen'this 3 30 R. Pf M. speed is reached.

Without our novel unloader it required'an 18Inile per hour wind to sternum impeller.

=The windmill would then continueto-pump water doWn to .a'iour orYfiveinile, penhour :wind. C'However; due to the fact that there was no reduction of s'troke length at this'low wind valuefthe propellenbec'ame rapidly overloaded and consequentlyistopped. This resulted in no water-being pumped until another 18 mile'per hour breeze came-up.

It will, therefore,be evidentthat during any continued lOW wind period when perhaps for days at a timethe 'Wind'never'reaches 'a'velocity above eight to 'tenniiles per hour,

the ordinary vvindmillwheel is incapable of starting due to the-magnitude of the load connected thereto. By using our disconnect device or unloader itis'pos'sible to not'only 'permit the impeller to turn during these loW' wind periodsbut "alsoto' pump considerable water. Then, too, the amount of water pumped is greatlyincreased dueto" our device automatically decreasing the stroke Of 'the plunger rod during low jwind periods,

thus" preventing the impeller from coming to -velocity.above two miles per hour. 4 In Fig"; 8 We have'illus'tr-ateddiagrammati- V cally af nodifiedform 'of'unloader or clutch.

In this construction the impeller driven shaft 125has secured thereto a rotary pump men'iber 126 having a-plurality of reciprocatory vanes or paddles 127. The-member 126is mounted 'eccentrically in a housing 128 which issuitably connected to the object or-load' to be turned which, for example,mny taket-he' form of a'pump drive or like load where the-starting torque required 'is relatively high.

The casino; or housing 128 is provided with a U-shapedpassageway-orby-pass 129 which "5 "motor, the shaft f 125 will: rotate nela tively slowly. 'I he-pump member 126 will rotate with the-shaft and pum non-froezing liquid or oil 133- around through the spessageway or by-pass 129 since the va'lve' 132 normally open. Assoonas the impellerieaiches a given speed, the liquid pressure in .the thy-pass 129 will be sufiiciently great to overcomeithe'tensum of valve 132. thus causing it to ktlosc.

Thereafter the h'ousing 128 and "member 196 willrotate asa unit-with the-Shaft 125::th11s connecting theload to the-iimpel'lewshaft 125.

Attention is called to the fantithat the sensi- -tive element comprises a valve/73 of relatively large'ereaand small li-ftiproviding arelatively large opening for the allow :of the toil *therethrough: onlow velocities or ditfiercnoes 'of pressure. Due :to ?the z'large :ureawhich this valve has, and the smallliftarequired to close it, thejdeviceis verysensitive and avill close quickly and: with but alittledoss of (Oil as-soon asithe proper velocityisaieached.

' Attention is called tothe'faet thatithe-in- --ner hollow pi-ston'bl at all 'ti'mes has a-very-substantial guide infthe' cylinder 55, so'that the "tendency to: cock oribinrl' is'greatly minimized and uneven wear is prevented. *At 'thesame time, due to th-isla-rge guide' between: the two parts, a tightj oint between them may bemaim tained overlong periods :of time.

By keeping the 'level'oftthe oil 'below thetop 102 of theouter cylinder 55, the joint between the pistonSand-cylinder lSTDOt subtimes to :cause lea-kagemnd also it is possible, bykeeping' thelevel belowvthe drain,- hole 65, to permit any excess of oihto be scraped Y Oil "and :returned ito the inside 'ofthmhollew cylinder 57. I

This modificatiom ot "our :invdntio11-tlaows that our invention eax'rrbe HtlllZQdrtO connect ithemtaryshaftaof thei imp'ellento a :loadtto be rotated as well as: to a-reoiprooatory load. 1 I have shown-the pistonas-hollowto receive- This :valve, 80

a Upon the startmg of the impeller 1 or other 0 j ected to the hydrostatic head, operating-at all the oil discharged from the cylinder. viously, the lnvention is not to be limited to this specific construction I may employ a piston in a double acting cylinder, the oil being driven from the closed end of the cylinder to the end into which the piston rod enters through a lay-pass which may be in the piston. or i na separate connection as shown for example in the bypass in Fig. 8.

lVe desire it understood that our invention is not to be limited by the present disclosure of our preferred modification of the invention, but only in so far defined by the scope and spirit of the appended claims.

o claim 1. In combination, a piston, a cylinder therefor, a valve positioned in the end of the piston within the cylinder, tension means of a predetermined value for normally maintaining the valve open, said cylinder being adapted to contain an incompressible liquid, a flange carried by the free end of the piston, a first crosshead associated with said cylinder flange, truss rods, extending through apertures in said cylinder flange for connecting said crosshead to said piston flange, a second crosshead associated with said piston flange, truss rods extending through apertures in said piston flange for connecting said second crosshead to said cylinder flange and means for causing a relative moving between said piston and said cylinder, said truss rods serving to guide said piston and cylinder.

2. 'In combination, a tubular piston, a cyl inder telescoped by the said piston, valve mechanism associated with the end of the piston inside of the said cylinder, an incompressible liquid carried by the said cylinder, said piston having formed intermediate its ends in its wall a plurality of down wardly slanting holes communicating at their uppermost ends with an annular groove formed in the outer periphery of the piston, said cylinder having an annular groove formed in its inner wall adapted to cooperate with the annular groove of the piston, and means for causing a relative movement between the piston and the cylinder.

3. In combination, a pair of telescoping members, an incompressible liquid in one of said members, and valve mechanism in the other of said members, one of said members having a plurality of inclined holes communicating with an annular groove formed in the periphery of the said member, and the other member having an annular groove formed in its inner periphery adapted to cooperate with the annular groove in said other member, said grooves being adapted to discharge any of the liquid getting between the telescoping walls of the two members back into the inside of the members.

4. In combination, a cylinder, a piston telescoping said cylinder, an incompressible liquid in said cylinder, valve mechanism in said piston adapted to be closed when the liquid attains a given value, and means for causing relative movement between the piston and the cylinder, said cylinder having an annular groove formed in its inner wall adjacent its upper end and said piston having formed in its outer wall an annular groove adapted to cooperate with the said annular groove of the cylinder, said piston also having a plurality of inclined holes communicating with its annular groove, said grooves cooperating to collect any liquid getting between the telescoping walls of said cylinder and piston, and said inclined holes serving to discharge the liquid so collected into the said cylinder.

5. In combination, a cylinder, a piston telescoping said cylinder, an incompressible liquid in the said cylinder, valve mechanism associated with said piston including a valve and tension means, and means for causing relative movement between the cylinder and the piston to cause the liquid in the cylinder to be displaced by the piston, said piston being provided with a bore adapted to receive said displaced liquid, said valve mechanism controlling the displacing of the liquid from the cylinder into the piston, said valve having a small drain aperture permitting the liquid trapped in the cylinder to be returned to the piston.

6. In combination, a pair of telescoping members, each of said members being provided with. a flange portion, means for causing a relative movement between said members, an incompressible fluid in one of said members, valve mechanism in the other member, and a collapsible dust cover secured at its ends to said flange portions for enclosing the peripheral portions of said telescoping members.

7. In an unloader, an outer cylinder and an inner hollow piston, said piston having a head comprising a by-pass port, a poppet valve of relatively large area and relatively small lift governing said. port, said cylinder being adapted to be filled with liquid to a point below its upper end and to extend up to the piston head.

8. In an unloader, an outer cylinder, an inner hollow piston closely fitting the cylinder, a head member separately connected to the lower end of said piston, said head member having a by-pass port of relatively large area extending therethrough, a conical poppet valve of relatively small lift carried by said head member and governing said port, spring means for holding the valve away from the port, said cylinder being adapted to be filled with liquid up to the head and to a point below its upper end, said piston extending into the cylinder a substantial distance at all times to provid a relgltively long id b wee h m.

9. In,en' unloader, a, cylinder member, e hollow piston member projecting into the 215 cylinder memberend ,hauing ayhead at its end furthest in the cylinder member,n body of liquid disposed Wholly ithin the cylinder, and acheck-valved bypass insaid heed, seidc'heck alve having ereletively large ;-;10-.die1 11eter and relatively small lift, and a leakttge passageway x independentof seidyttlve for permittingslow leakage vof liquid trapped ,inthe cylinder to relieve the pressure upon the checkyalveto permit ittoopenmvhen the parts stand .motionless.

'10. As a means for connecting a 'motor withe; punipplunger, a pair of plunger rod sections, a cylinder member fecingupwardly, 'a hollow piston member extending downinto 2130 the cylinder member, sa id members haying bases, cross bars connectedito thecplunger rod sections, connecting rods connecting the cross bars with the bases, the connecting rods secured ,to one end being guided in openings gs inthe-other base and vice versa, said piston member havinga'hea-d at its lower end, said headzbeing disposed at all times Within the cylinder, vand a -velocity controlled by-pass insaidv cylinder vhead to permit the by-pass- 50 glng' of fluid from the cylinder to the vinterior ofthe pistonbelown given Velocity of fluid through the bypass.

-11.;As a meansfor connecting a motor With a pump plunger, a pair of plunger rod -55 sections, a cylinder member facing upwardlyga hollow piston member extending down into the cylinder member seid members having bases, cross bars connectedto theplunger rod sections, connecting rods connecting the Q40 cross bzirs with the,beses,.the connectingrods secured to, one end being guided in openings .in the othervbase-zand vice Verse seid piston .-member haying a head .atvits lower en'd,sai d head being disposed at ell times Within the 5 cylinder, ende velocity controlled by-pass in said cylinder head to permitlhe by-passging of/fluid from the cylinder to the interior of the piston below a given velocity of fluid through'th e by-pass, said Velocity conbotrolled by-pass comprising e check Valve of large ,area and smallllift, and a body of fluid filling a part only of thecylinder, snidheed having a bypass constantly. open independ- .ently of said check ya'lve to prevent con- 65 tinned-locking of the parts together by holdingof the valveto-its seat when the parts are not in motion.

In witness whereof, 1 we hereunto subscribe our names this klthday of September, 1926. '60 HERBERT E BUCKL EN.

HARLlE O. PUTT. 

